Below are nitrate concentrations in the Embarras River, sampled at Camargo, since 1993. Concentrations are usually above the drinking water standard of 10 mg N/L every winter and spring, when tiles are flowing. They then decrease in summer to near zero, when there is little flow. This watershed loses about 25 to 30 lbs of N per acre each year (30 kg N/ha/yr), or a total of about 2000 tons of N each year (4 million lbs), well over a million dollars worth each year.
We also can see the long-term history of nitrate concentrations in the Embarras River by using Illinois State Water Survey, Illinois EPA, and USGS data. This is what the look term record looks like, and the increase in nitrate concentrations through the 1960s and on follows the increase in nitrogen fertilizer use.
Last modified August 31, 2016